Multimedia Messaging Service MMS has in its present form been defined in standard 3GPP TS 23.140 “3rd Generation Partnership Project; Technical Specification Group Terminals; Multimedia Messaging Service (MMS); Functional description; Stage 2 (Release 6)”. The architecture of the networks involved as well as functions of different modules, especially the MMS User Agent and the MMS Relay/Server (below referred to as MMS Server), are described in more detail therein.
Notifications of incoming MMS messages are delivered from the MMS server to the MMS User Agent by using WAP push. The MMS User Agent sends a WAP or HTTP GET in order to make the MMS server send an MMS message.
The transfer of Multimedia Messaging Services MMS messages is usually performed using the Wireless Application Protocol WAP or Hypertext Transport Protocol HTTP. Retrieval of an MMS message is then performed by sending a WAP or HTTP GET request, respectively.
Messaging services implemented for the IP Multimedia core network Subsystem IMS network are currently under discussion in the 3GPP. The IMS messaging services comprise messaging types immediate messaging, deferred delivery messaging, and session-based messaging. In immediate messaging, a message is delivered immediately from one user to another, whereas in deferred messaging it is delivered as soon as the recipient becomes available. In session-based messaging, a session has to be set up before any other communication can take place.
In the IMS network, the Session Initiation Protocol SIP is used for creating, modifying, and terminating sessions with one or more participants. Two methods defined in the SIP are SUBSCRIBE and NOTIFY. SUBSCRIBE is used by a subscriber terminal to subscribe to event packages at proxies or servers. Whenever an event belonging to the subscribed event package is triggered, the terminal is informed by using the SIP method NOTIFY.
It may be commercially of vital importance to be able to retrieve MMS messages directly from within IMS. This has, nevertheless and in spite of hard work, been impossible until now.